1. Field of the Invention
The subject invention relates to methods and apparatus for controlling peripheral units in a telecommunication system, such as in a centrally controlled telecommunication or telephone exchange having two or more like control apparatus and having the peripheral units assembled in groups, each of which is associated with its own switching means for selectively connecting the particular group to the control apparatus.
2. Description of the Prior Art
For safety reasons, it is customary to provide the control apparatus necessary for the control of telecommunication installations in multiple form, whereby one control apparatus is always in operation and the remaining control apparatus are in reserve on a stand-by basis. A given control apparatus remains then in operation until monitoring equipment, which supervises all control apparatus, detects a disturbance or defect in the particular control apparatus then in operation, disconnects the same and permits another control apparatus to take over the operation of the defective, disconnected apparatus.
In that prior-art system, the unverifiable and therefore uncertain preparedness of the control apparatus standing by in reserve is disadvantageous and effectively results in a reduction of the safety margin. Furthermore, in the case of electro-mechanical control apparatus, a very uneven wear of the individual control apparatus takes place, since a control apparatus which is constantly in operation obviously attains a considerably higher number of switching cycles than a stand-by reserve control apparatus which takes over the control operation only in case of trouble.